Depending on how similar treatments are, and on demand from doctors and patients, biosimilar pricing could more closely track the face-off among branded drugs, Brennan said in an interview on Wednesday.
Generic versions of traditional pharmaceuticals can usher in discounts of as much as 98 percent. Biosimilars retain a much higher margin due to their more complicated manufacturing process, which can create a new version of a biotechnology drug but not an exact copy.
"As a result of that, with these new ones coming on we are probably going to be seeing something that looks like more of a situation where there are multiple brands," Brennan said. "In the past that didn't give you 98 percent discounts. In the past, that would give you 40 to 50 percent discounts."
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The U.S. Food and Drug Administration approved on Friday the first biosimilar drug for use in the country, a copy of Amgen's Neupogen cancer treatment that was made by Novartis. Pricing on the biosimilar has yet to be determined.
Drugmakers that are racing to develop biosimilars include Pfizer and Hospira. In Europe, Hospira already sells copycat versions of Neupogen and Merck's and Johnson & Johnson's arthritis drug Remicade. Other biosimilar players include Amgen, Biogen Idec, Teva Pharmaceuticals Industries, and Mylan.
Biologic drugs have already been approved in Europe, but pricing varies as each country has a role in negotiating drug costs.
Earlier this year, Express Scripts and CVS pitted two novel treatments for hepatitis C against each other to wrest large price cuts from their manufacturers, Gilead Sciences and AbbVie.
Brennan said they are likely to use similar tactics as more biosimilars enter the marketplace. That could mean excluding one of the drugs from their reimbursement list for most patients, requiring patients to try the less expensive treatment first or insisting they give prior approval before a patient begins the medication based on their specific medical history, he explained.